Talk to Urologist on ERECTION ISSUES

i did masterbution for around 10 years than suddenly i lost my strong erection i heavily eat junk food drinks etc from 1 year i'm facing erection issues and i left masterbution or do it rarely i want to resolve this issue what you suggest , i started exercise in the gym and walk i'm going to marry in 3 years , in my point of view i think this is because of the low testosterone level.. but you can guide me well